Headlight modulator regulations and laws for motorcycles

Print this page and carry it with you if needed.

The law and the headlight modulator

Our headlight modulator does not have a feature allowing you to operate the horn or some other button to initiate the modulator for a few seconds, or a burst, because this feature is not legal... especially at night.
We don't offer different modulations rates. 240 cycles per minute are all that is legal. Faster/slower is ILLEGAL.

If we did offer you this as an added feature the modulators would not be in compliance with the d.o.t. regulations which means you wouldn't have a defense should you get stopped or receive a citation from your local trooper. Don't just take our word or anyone else's on this issue. You should check with the d.o.t.

At Kriss Industries we build our modulators in strict adherence to the federal standards!
The government sets the standards and the manufacturer is supposed to comply and then state that the item is "in compliance". However, the government does not examine each product on the market for compliance and "never" approves a specific product. If you're told that the d.o.t has approved an individual product you are not being provided truthful information.

If you find a modulator with more features than ours then that modulator is not in compliance with the law!

Headlight Modulators "are legal" if they meet the d.o.t. requirements. (see below for short version of the U.S. rules)

* Modulation of lights other than the headlamp may or may not be legal in all areas.
We cannot advise as to the legality as to what is considered part of the headlight system other than the headlight.

Do you need information about the United States Federal Regulations?

A copy of these standards may be obtained by writing the d.o.t. in Washington, D.C. or clicking on the following title
http://www.access.gpo.gov/nara/cfr/cfr-retrieve.html#page1
(enter 49 in the title box, 571 in the part box, 108 in the section box and then click the Retrieve button)
(when you get to the page scroll down to paragraph S7.9.4)

We cannot assure that these links will not change over time.

FMVSS 108 (Federal Motor Vehicle Safety Standards) (49 CFR Part 571.108 S7.9.4) allows motorcycle headlight modulation systems in all 50 states provided they comply with the standards set forth in this section.

Title 49 USC 30103(b1) (US Codes) prohibits any state from forbidding a system that conforms to FMVSS 108.

Do you need information about rules in

Canada prescribes the same standards as the US and allow modulators meeting these standards.
http://www.tc.gc.ca/roadsafety/mvstm_tsd/tsd/1080rev4_e.htm#_Toc%20S7.9
The standard is found under S7.9.4

TITLE 49--TRANSPORTATION

CHAPTER V--NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION,
DEPARTMENT OF TRANSPORTATION

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS--Table of Contents

Subpart B--Federal Motor Vehicle Safety Standards

Sec. 571.108 Standard No. 108; Lamps, reflective devices, and associated equipment.

S7.9.4 Motorcycle headlamp modulation system.
S7.9.4.1 A headlamp on a motorcycle may be wired to modulate either the upper beam or the lower beam from its maximum intensity to a lesser intensity, provided that:
    (a) The rate of modulation shall be 240 plus-minus 40 cycles per minute.
    (b) The headlamp shall be operated at maximum power for 50 to 70 percent of each cycle.
    (c) The lowest intensity at any test point shall be not less than 17 percent of the maximum intensity measured at the same point.
    (d) The modulator switch shall be wired in the power lead of the beam filament being modulated and not in the ground side of the circuit.
    (e) Means shall be provided so that both the lower beam and upper beam remain operable in the event of a modulator failure.
    (f) The system shall include a sensor mounted with the axis of its sensing element perpendicular to a horizontal plane. Headlamp modulation shall cease whenever the level of light emitted by a tungsten filament light operating at 3000 deg. Kelvin is either less than 270 lux (25 foot-candles) of direct light for upward pointing sensors or less than 60 lux (5.6 foot-candles) of reflected light for downward pointing sensors. The light is measured by a silicon cell type light meter that is located at the sensor and pointing in the same direction as the sensor. A Kodak Gray Card (Kodak R-27) is placed at ground level to simulate the road surface in testing downward pointing sensors.
    (g) When tested in accordance with the test profile shown in Figure 9,the voltage drop across the modulator when the lamp is on at all testconditions for 12 volt systems and 6 volt systems shall not be greater than .45 volt. The modulator shall meet all the provisions of the standard after completion of the test profile shown in Figure 9.
    (h) Means shall be provided so that both the lower and upper beam function at design voltage when the headlamp control switch is in either the lower or upper beam position when the modulator is off.
    S7.9.4.2(a) Each motorcycle headlamp modulator not intended as original equipment, or its container, shall be labeled with the maximum wattage, and the minimum wattage appropriate for its use. Additionally, each such modulator shall comply with S7.9.4.1 (a) through (g) when connected to a headlamp of the maximum rated power and a headlamp of the minimum rated power, and shall provide means so that the modulated beam functions at design voltage when the modulator is off.
    (b) Instructions, with a diagram, shall be provided for mounting the light sensor including location on the motorcycle, distance above the road surface, and orientation with respect to the light.